In many areas of the world, there is a shortage of potable water. Additionally, the supply of water in boats and recreational vehicles is limited by the size of on-board tanks. In order to maximize the available water, people attempt to minimize the time the water is running. When a separate handle for hot and cold water is used, each time the water is turned on and off, the temperature has to be readjusted. The process results in excess use of water. In the case where there is a single mixing valve, there is a tendency to not turn the water off without conscious thought. Furthermore, children often have difficulty reaching the back of the sink to turn a valve on and off, and some disabled people do not have enough control of their hand movement to satisfactorily operate normal faucet controls. As a result water is wasted unnecessarily.
There has been a need for an inexpensive water saving valve which can be easily attached to existing faucets, such as kitchen sink faucets, for example, and is convenient to use. This need is not met adequately by faucet valves designed to sense the presence of a potential user, or those having a self-closing foot operated valve or switch, or those having a timing mechanism.
U.S. Pat. No. 4,181,987 discloses an add-on valve mechanism which can be easily mounted between the faucet spout and outlet nozzle on a sink fixture. It comprises a spring-loaded ball which can be unseated from a conical valve seat by manual operation of a flip lever on the side of the valve housing. The device has a snap action and is designed to have its valve remain either in a full-on or full-off position until the operator applies a force to the flip lever. The flip-action swing range of the flip lever from the full-off position before it flips completely to the full-on position does not permit the operator to conveniently push the lever to only a partly-on self-closing position while collecting the flowing water or washing with it.